Have some fun with this. Put on a gray pin stripe suit and look the Wall Street image. Explain to your congregation that you are having a stockholder's meeting. Explain that stockholders own the company and have a vested interest in the company doing well. "This church will prosper in great ways as the youth prosper. We want to offer you the opportunity to invest in these youth. So we are selling stock to allow these kids to go on an incredible mission trip" (or choir tour, or youth camp, etc). You get the idea. Really do it up.
Have with you a stock certificate. You can get blank certificates in full color at any office supply store. Print them with the name of the church and whatever else you want. Fill in the "stockholder's" name and dollar amount of his or her investment. Give each person a certificate and ask for prayer for the event.
Before dismissing the service, give all the stockholders a "stock holder's report" -- a list of participating students and leaders who are going on the trip. The certificate doubles as a prayer reminder.
When the group returns, hold a stockholder's meeting and talk about the incredible dividends earned from their investment. The congregation will eat up this stuff, and the visibility and interaction with be invaluable.
For more info, see Enablers Youth Ministry Coaching